KR20060040705A - Viscosity reducible radiation curable resin composition - Google Patents

Abstract

The invention relates to a viscosity reducible radiation curable composition comprising at least one radiation curable component and a filler, wherein the composition has the properties i) a yield stress value of < 1100 Pa, ii) a viscosity (at a shear rate of 1 sec between 1 and 1500 Pa.sec, and iii) a filler settling speed less than 0.3 mm/day.

Description

Viscosity reducing radiation curable resin composition {VISCOSITY REDUCIBLE RADIATION CURABLE RESIN COMPOSITION}

The present invention relates to a viscosity reducing radiation curable resin composition and its use in a method of producing a three-dimensional object.

Viscosity reducing radiation curable resin compositions are known from US Pat. No. 5,474, 719, which is incorporated herein by reference. Disclosed are compositions comprising materials that induce viscoelastic flow behavior. The composition has a much lower viscosity at low shear rates (eg, 5,440 centipoise at 3 rpm, Brookfield viscosity experiments) and higher shear rates (eg, 1,420 centipoise at 30 rpm). The difference in reported viscosity (centipoise) is about 2-4 at these shear rates. The composition is a paste in the absence of shear. U.S. Patent No. 20020195747 discloses a novel solid freeform fabrication tool that largely forms three-dimensional objects from sticky paste-like materials. The paste contains fillers and has a viscosity of greater than 10,000 centipoise at room conditions. The paste material cannot be handled in conventional optical molding machines designed to handle liquid resins.

Purpose of the Invention

It is an object of the present invention to provide a radiation curable composition which contains an inorganic filler, exhibits viscoelastic behavior and has a low yield stress. The composition preferably exhibits excellent storage and application stability.

It is another object of the present invention to provide a composition having viscoelastic properties, containing at least one filler and which can be applied to conventional SL-groups to produce three-dimensional objects.

Summary of the Invention

The present invention provides a viscosity reducing radiation curable composition comprising at least one radiation curable component and a filler,

Yield stress value less than 1100Pa,

Viscosity (at shear rate of 1 second ^-1 ) 1 to 1500 Pa.sec and

The composition relates to a composition having a filler fixation rate of less than 0.3 mm / day.

A second aspect of the invention is a viscosity reducing radiation curable composition comprising at least one radiation curable component and a filler,

Yield stress value less than 1100Pa,

Viscosity (at shear rate of 10 seconds ⁻¹ ) 1 to 200 Pa · sec and

It relates to a composition having a property of less than 0.3 mm / day filler fixation rate.

Detailed description of the invention

The composition of the present invention is radiation curable and contains at least one radiation curable component. Examples of radiation curing components are cationic polymerization components and radical polymerization components.

(A) cationic polymerization component

Cationic polymerization components (hereinafter also referred to as component (A)) are organic compounds which, when irradiated with light, polymerize or crosslink in the presence of a cationic polymerization initiator. Examples of cationic polymerization components include epoxy compounds, oxetane compounds, oxolane compounds, cyclic acetal compounds, cyclic lactone compounds, thiirane compounds, ethane compounds, vinyl ether compounds and cyclic thioether compounds. Among the above compounds, the presence of an epoxy compound and / or an oxetane compound is preferable, because the curing rate of the produced resin composition is high, and the cured resin obtained from the resin composition has good mechanical properties.

Epoxy compounds which can be used as component (A) are, for example, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, brominated bisphenol S diglycidyl ether, epoxy novolak resin, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, 3 , 4-epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexane carboxylate, 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexane-meth-dioxane, Bis (3,4-epoxycyclohexylmethyl) adipate, vinylcyclohexene oxide, 4-vinylepoxycyclohexane, bis (3,4-epoxy-6-methylcyclohexyl-methyl) adipate, 3,4-epoxy -6-Methylcyclohexyl-3 ', 4'- Epoxy-6'-methyl cyclohexane carboxylate, methylenebis (3,4-epoxycyclohexane), dicyclopentadiene diepoxide, ethylene glycol die (3,4-epoxycyclohexylmethyl) ether, Ethylene Bis (3,4-Epoxycyclohexanecarboxylate), Epoxy-hexahydrodioctyl phthalate, Epoxyhexahydrophthalic acid di-2-ethylhexyl, 1,4-butanediol diglycidyl ether, 1,6- Hexanediol diglycidyl ether, glycerol triglycidyl ether, trimethyllopropane triglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, one or more types Polyglycidyl ethers of polyether polyols obtained by addition of alkylene oxanes to fatty acid polyhydric alcohols such as ethylene glycol propylene glycol and glycerol; Diglycidyl esters of fatty acid hair chain diacids; Mono glycidyl ethers of fatty acid higher alcohols; Monoglycidyl ethers of polyether alcohols obtained by adding phenol, cresol and butyl phenol and alkylene oxides thereto; Glycidyl esters of higher fatty acids; Epoxidized soybean oil, epoxy stearate butyl, epoxy stearate octyl, epoxidized flaxseed oil and epoxidized polybutadiene.

Among the above compounds, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, 3,4-epoxycyclohexyl methyl-3 ', 4'-epoxycyclohexane carboxylate, bis (3,4-epoxycyclohexylmethyl) adipate, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol Triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether and polypropylene glycol diglycidyl ether are preferred.

Examples of oxetane compounds include trimethylene oxide, 3,3-dimethyl oxetane, 3,3-dichloro methyl oxetane, 3-ethyl-3-phenoxy methyl oxetane, bis (3-ethyl-3-methyl Oxy) butane, 3-ethyl-3-hydroxymethyloxetane, 3- (meth) allyloxymethyl-3-ethyloxetane, (3-ethyl-3-oxetanylmethoxy) methylbenzene, (3-ethyl -3-oxetanylmethoxy) benzene, 4-fluoro- [1- (3-ethyl-3-oxetanylmethoxy) methyl] -benzene, 4-methoxy- [1- (3-ethyl-3- Oxetanylmethoxy) methyl] benzene, [1- (3-ethyl-3-oxetanylmethoxy) ethyl] phenyl ether, isobutoxymethyl (3-ethyl-3-oxetanylmethyl) ether, asabor Nyloxyethyl (3-ethyl-3-oxetanylmethyl) ether, isobornyl (3-ethyl-3-oxetanylmethyl) ether, 2-ethylhexyl (3-ethyl-3-oxetanylmethyl) Ether, ethyldiethylene glycol (3-ethyl-3-oxetanylmethyl) ether, dicyclopentadiene (3-ethyl-3-oxetanylmethyl) ether, dicyclophene Tenyloxyethyl (3-ethyl-3-oxetanylmethyl) ether, dicyclopentenyl (3-ethyl-3-oxetanylmethyl) ether, tetrahydroperfuryl (3-ethyl-3-oxetanylmethyl ) Ether, tetrabromophenyl (3-ethyl-3-oxetanylmethyl) ether, 2-tetrabromophenoxyethyl (3-ethyl-3-oxetanylmethyl) ether, tribromophenyl (3-ethyl- 3-oxetanylmethyl) ether, 2-tribromophenoxyethyl (3-ethyl-3-oxetanylmethyl) ether, 2-hydroxyethyl (3-ethyl-3-oxetanylmethyl) ether, 2 -Hydroxypropyl (3-ethyl-3-oxetanylmethyl) ether, butoxyethyl (3-ethyl-3-oxetanylmethyl) ether, bentaalcolophenyl (3-ethyl-3-oxetanylmethyl ) Ether, pentabromophenyl (3-ethyl-3-oxetanylmethyl) ether, bornyl (3-ethyl-3-oxetanylmethyl) ether, 2-phenyl-3,3-dimethyl-oxetane And 2- (4-methoxyphenyl) -3,3-dimethyl-oxetane.

Oxetanes containing two or more oxetane rings in a molecule are, for example, 3,7-bis (3-oxetanyl) -5-oxa-nonane, 3,3 '-(1,3- (2-methyl Lenyl) propanediylbis (oxymethylene)) bis- (3-ethyloxetane), 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, 1,2-bis [( 3-ethyl-3-oxetanylmethoxy) methyl] ethane, 1,3-bis [(3-ethyl-3-oxetanylmethoxy) methyl] propane, ethylene glycol bis (3-ethyl-3-jade Cetanylmethyl) ether, dicyclopentenyl bis (3-ethyl-3-oxetanylmethyl) ether, triethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, tetraethylene glycol Bis (3-ethyl-3-oxetanylmethyl) ether, tricyclodecanediyldimethylene (3-ethyl-3-oxetanylmethyl) ether, trimethylolpropane tris (3-ethyl-3-oxeta Nylmethyl) ether, 1,4-bis (3-ethyl-3-oxetanylmethoxy) butane, 1,6-bis (3-ethyl-3-oxetanylmethoxy) hexane, pentaerythritol Tris (3-ethyl-3-oxetanylmethyl) ether, pentaerythritol tetrakis (3-ethyl-3-oxetanylmethyl) ether, polyethylene glycol bis (3-ethyl-3-oxetanylmethyl ) Ether, dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol pentakis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol tetrakis ( 3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol pentakis ( 3-ethyl-3-oxetanylmethyl) ether, ditrimethylolpropane tetrakis (3-ethyl-3-oxetanylmethyl) ether, ethoxylated bisphenol A bis (3-ethyl-3-oxetanylmethyl ) Ether, propoxylated bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, epoxidized hydrogenated bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, propoxylated Digestion bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, and epoxidized bisphenol F (3-ethyl-3-oxetanylmethyl) include ether.

Cationic polymeric compounds may be used alone or in combination of two or more.

The component (A) content of the resin composition of the present invention may be in the range of 10 to 95% by weight, preferably 30 to 90% by weight, more preferably 40 to 85% by weight.

(B) cationic photopolymerization initiator

When the cationic polymerization initiator component (A) is present, the composition preferably also contains a cationic photopolymerization initiator (B). In the compositions according to the invention any type of photoinitiator which forms a cation which initiates the reaction of the cationic polymerization component (A) upon exposure to actinic radiation can be used. Many cationic photoinitiators for suitable epoxy resins are known and proven in the art. These include, for example, weak nucleophilic cations and onium salts. Examples include halonium salts, iodosyl salts or sulfonium salts, as described in published European Patent Publications EP 153904 and WO 98/28663, published European Patent Publications EP 35969, 44274, 54509. Sulfoxium salts, as described in US Pat. No. 164314, diazonium salts as described in US Pat. Nos. 3,708,296 and 5,002,856. Other cationic photoinitiators are metallocene salts, as described in published European patent publications EP 94914 and 94915.

Studies of other conventional onium salt initiators and / or metallocene salts can be found in "UV Curing, Science and Technology", (Editor SP Pappas, Technology Marketing Corp., 642 Westover Road, Stamford, Conn., USA) or [ "Chemistry & Technology of UV & EB Formulation for Coatings, Inks & Paints", Vol. 3 (edited by P. K. T. Oldring). Preferred cationic photoinitiators (B) are onium salts represented by formula (I):

[R ¹ _a R ² _b R ³ _c R ⁴ _d Z] ^{+ m} [MX _n ] ^-m

Where

The cation is onium;

Z is S, Se, Te, P, As, Sb, Bi, O, I, Br, Cl or N≡N;

R ¹ , R ² , R ³ and R ⁴ represent the same or different organic acid;

a, b, c and d are each an integer of 0 to 3;

(a + b + c + d) is equal to the valence of Z;

M represents a metal or metalloid which is the central atom of the halide complex, for example B, P, As, Sb, Fe, Sn, Bi, Al, Ca, In, Ti, Zn, Sc, V, Cr, Mn and Co;

X represents halogen;

m is the net electrical charge of the halide complex ion;

n is the number of halide atoms in the halide complex ion.

Examples of the anion (MX _n) In the formula is tetrafluoroborate (BF ₄ ^-), hexafluoro flu in Oro phosphate (PF ₆ ^-), antimonate hexafluorophosphate (SbF ₆ ^-), it is Senate hexafluoro (ASF ₆ ⁻ ) and hexachloroantimonate (SbCl ₆ ⁻ ).

It is also possible to use onium salts having an anion represented by the formula [MX _n (OH) ^- ]. Additionally, the perchlorate (ClO ₄ ^-), methanesulfonic acid ion-trifluoromethyl (CF ₃ SO ₃ ^-), sulfonate ion fluoro (FSO ₃ ^-), toluenesulfonic acid ion, benzenesulfonic acid ion, and tri-to tri-nitro Onium salts with other anions such as nitrotoluene sulfonic acid ions can also be used.

Cationic photopolymerization initiators can be used alone or in combination of two or more.

The component (B) content of the resin composition of the present invention may be in the range of 0.1 to 10% by weight, preferably 0.2 to 5% by weight, more preferably 0.3 to 3% by weight.

(C) radical polymerization component

The present invention includes at least one free radical curing component, for example at least one free radical polymerization component having at least one ethylenically unsaturated group, such as a (meth) acrylate (ie acrylate and / or methacrylate) functional component. can do. The free radical polymerization component can have one or more radical polymerization groups. Non-limiting examples of monofunctional (meth) acrylates are isobornyl (meth) acrylate, lauryl (meth) acrylate and phenoxyethyl (meth) acrylate.

Polyfunctional monomers that can be used for component (C) include ethylene glycol di (meth) acrylate, dicyclopentenyl di (meth) acrylate, triethylene glycol diacrylate, tetraethylene glycol die (Meth) acrylate, tricyclodecanediyldimethylene di (meth) acrylate, tris (2-hydroxyethyl) isocyanurate di (meth) acrylate, tris (2-hydroxyethyl) isocyanate Late tri (meth) acrylate, caprolactone-modified tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, ethylene oxide (hereinafter also short Referred to as EO-modified trimethylolpropane tri (meth) acrylate, propylene oxide (hereinafter also referred to briefly as PO)- Modified trimethylolpropane tri (meth) acrylate, tripropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, bisphenols with (meth) acrylic acid adducts at both ends A diglycidyl ether, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra ( Meth) acrylate, polyester di (meth) acrylate, polyethylene glycol di (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerytate Lithol tetra (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol penta (meth) a Relate, Ditramethylolpropane Tetra (meth) acrylate, EO-Modified Bisphenol A Di (meth) acrylate, PO-Modified Bisphenol A Di (meth) acrylate, EO-Modified Hydrogenated Bisphenol A Di (Meth) acrylates, PO-modified hydrogenated bisphenol A di (meth) acrylates, EO-modified bisphenol F di (meth) acrylates and (meth) acrylates of phenol novolak polyglycidyl ether.

Multifunctional monomers having three or more functional monomers for this purpose are among the tri (meth) acrylate compounds, tetra (meth) acrylate compounds, penta (meth) acrylate compounds and hexa (meth) acrylate compounds described above. You can choose from one. Among them, trimethylolpropane tri (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate And ditrimethylolpropane tetra (meth) acrylate are particularly preferred.

The monofunctional and multifunctional monomers of component (C) may be used alone or in combination of two or more, the amount of such component (C) is preferably 5 to 50% by weight, alternatively 7 to 25% by weight, more preferably Is 10 to 20% by weight.

(D) radical photopolymerization initiator

When the radical polymerization component (C) is present, the composition preferably also contains a radical photopolymerization initiator (D). In the compositions according to the invention, any type of photoinitiator which forms a radical which initiates the reaction of the radical polymerization component (C) upon exposure to actinic radiation can be used.

Radical photopolymerization initiators that can be used as component (D) include acetophenone, acetophenone benzyl ketal, anthraquinone, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, carbazole, Xanthone, 4-chlorobenzo-phenone, 4,4'-diaminobenzophenone, 1,1-dimethoxydeoxy-benzoin, 3,3'-dimethyl-4-methoxybenzophenone, thioxane Tone Compound, 2-Methyl-1,4- (methylthio) phenyl-2-morpholinopropan-2-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butane -1-one, triphenylamine, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-tri-methylpentyl phosphone oxide, Benzyl methyl ketal, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, fluorenone, fluorene, benzaldehyde, benzoyl ethyl ether, benzoin propyl ether, benzo Phenone, Michler ketone, 3-methylacet Combination and color sensitizers of tophenone, 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone (BTTB) and BTTB, such as xanthene, thioxanthene, coumarin and ketocoumarin It includes. Among the above compounds, benzyl methyl ketal, 1-hydroxycyclohexylphenyl ketone, 2,4,6-trimethylbenzoyl diphenylphosphine oxide and 2-benzyl-2-dimethylamino-1- (4-morpholino Phenyl) -butan-1-one is particularly preferred.

Radical photopolymerization initiators can be used alone or in combination of two or more.

The component (D) content of the liquid of the resin composition of the present invention is typically in the range of 0.01 to 10% by weight, preferably 0.1 to 8% by weight.

(E) filler

The filler of the resin composition of the present invention (hereinafter also referred to as component (E)) may be any material without specific limitation, but the inorganic material is in terms of water resistance function and mechanical properties of the three-dimensional object composed of the resin composition. Preferred at The filler may be present in any form of particles or as a powder, for example.

For example, silica particles having an average particle size or fiber length of 1 to 50 μm, such as fused silica and / or crystalline silica, can be used. Another example of a suitable filler is fused silica and / or crystalline silica and these powder particles are spherical.

Silica powder and other inorganic filler materials include polymers, inorganics, metals, metallic compounds, ceramics, or any combination thereof. Any polymer that can be used is thermoplastic, such as ABS, nylon, polypropylene, polycarbonate, polyethersulfate and the like. Some metallic powders or particles that can be used are steel, steel alloys, stainless steels, aluminum, aluminum alloys, titanium, titanium alloys, copper, tungsten, tungsten carbide, molybdenum, nickel alloys, lanthanum, hafnium, tantalum, rubidium, Bismuth, cadmium, indium, tin, zinc, cobalt, magnesium, chromium, gold, silver and the like. Some ceramics that can be used include aluminum nitride, aluminum oxide, calcium carbonate, fluoride, magnesium oxide, silicon carbide, silicon dioxide, silicon nitride, titanium carbide, titanium carbonitride, titanium diboride, titanium dioxide, tungsten carbide, tungsten trioxide, Zirconia and zinc sulfide. Some rare earth metal powders that can be used are cerium oxide, disphosphium oxide, erbium oxide, gadolinium oxide, holmium oxide, ruthetium oxide, samarium oxide, terbium oxide, yttrium oxide, etc., glass powder, aluminum, hydrated aluminum, magnesium oxide, Magnesium hydroxide, barium sulfate, calcium sulfate, calcium carbonate, magnesium carbonate, silicate mineral, diatomaceous earth, silicon sand, silicon powder, titanium oxide, aluminum powder, bronze, zinc powder, copper powder, lead powder, gold powder, silver dust, glass Fibers, potassium titanate single crystals, carbon single crystals, sapphire single crystals, single crystals behind confirmation, boron carbide single crystals, silicon carbide single crystals and silicon nitride single crystals.

The state of the surface of the particles of the filler used and the impurities contained in the filler in the production method can affect the curing reaction of the resin composition. In this case, it is desirable to wash the filler particles or coated particles with a suitable primer as a way to improve the curing properties.

These inorganic fillers may also be surfaces treated with silane coupling agents. Silane coupling agents that can be used for this purpose are vinyl trichlorosilane, vinyl tris (β-methoxyethoxy) silane, vinyltriethoxy silane, vinyltriethoxy silane, vinyl trimethoxy silane, γ- (methacryl Oxypropyl) trimethoxy silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxy silane, γ-glycidoxypropyltrimethoxy silane, γ-glycidoxy propylmethyl diethoxy silane, N- β (aminoethyl) -γ-aminopropyltrimethoxy silane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxy silane, γ-aminopropyltriethoxysilane, N-phenyl-γ-amino Propyl trimethoxy silane, γ-mercaptopropyl trimethoxysilane and γ-chloropropyltrimethoxy silane.

The inorganic fillers may be used alone or in combination of two or more. Inorganic fillers having different properties in combination can be used to provide the desired properties derived from the resin composition prepared from the filler. In addition, the resin compositions produced have significantly different fluidity, and when the grain size or fiber length distribution of the inorganic filler used is different, the average grain size or fiber length and amount are the same for the materials. Thus, by appropriately determining the grain size or fiber length distribution as well as the average grain size or fiber length, or by using inorganic fillers of the same material having different average grain size or fiber length in combination, the required amount and flowability of the filler And other properties of the resin produced can be adjusted as needed.

The component (E) content of the resin composition of the present invention is in the range of 10 to 95% by weight, 30 to 80% by weight, more preferably 50 to 70% by weight of the total composition.

(F) thixotropic agents

The resin composition of this invention contains the substance which acts as a thixotropic agent. Suitable thixotropic agents provide stable resins with or without limited fixation of the filler for an excess of time. Preferably, the pH of the material is less than 7, and may have no or limited effect on the light speed and mechanical properties produced by curing the resin with, for example, ultraviolet light. Preferably, the thixotropic agent exhibits rapid recovery of viscosity after application of shear to accelerate the photoshaping process.

Examples of suitable thixotropic agents include polyvinylpyrrolidone (similar to PVP K-15, K30 and K-90), titanate coupling agents (similar to Ken React LICA 38 and 55), aluminum Diesterates and aluminum triesters, copolymers with acid groups (Disperbyk-111), compounds with ionic groups (similar to Centrol 3F SB, Centrol 3F UB, and Emulmetik 120) , Flamed silicic acid (Aerosil 200), organic derivatives of castor oil (similar to ticksartol 1, ticsartrol ST, thixartrol GST and tiscin R) and polyoxyethylene-polyoxypropylene block copolymers (Pluronic (Pluronic, trade name). Preferred thixotropic agents are selected from the group consisting of thicinsin R, thixatrol 1, thixatrol GST, thixatrol ST, aluminum stearate 132 and 22, MPA 14, Ken Reacta 38 and KR 55. Most preferably, it is a thixotropic agent selected from the group consisting of thicinsin R, thixatrol 1, thixatrol GST and thixatrol ST.

Thixotropic agents are added in sufficient amounts to hinder the settlement of the filler. Typically thixotropic agents are from 0.1 to 10% by weight (relative to the total amount of the composition), preferably from 0.5 to 5% by weight.

(G) flow aids

The addition of thixotropic agents in an amount sufficient to interfere with the settling of the filler may generally provide a resin with high yield stress. Yield stress can be added to the flow aid to lower the resin's anti-seizure behavior without adversely affecting the viscoelasticity of the resin. Examples of suitable flow aids include low molecular weight polyacrylates (similar to Modaflow 2100, LG-99, Resin flow LF, and resin flow LV) or polyarylene oxide modified polydimethylsiloxanes ( Silwet L 7602). The flow aid is added in an amount of 0.01 to 5% by weight, preferably 0.02 to 1% by weight.

Optional Ingredients and Additives

The resin composition of the present invention may include optional components other than the components (A) to (G) described above within the limits in which they do not degrade the photo-curing properties of the resin composition. Optional components include photosensitizers (polymerization promoters) selected from the group consisting of amine compounds such as triethanolamine, methyl diethanolamine, triethylamine and diethylamine; Thioxanthone, derivatives of thioxanthone, anthraquinones, derivatives of anthraquinones, anthracenes, derivatives of anthracenes, perylenes, derivatives of perylenes, benzophenones, benzoin isopropyl ethers and reactive diluents such as vinyl ethers, Photosensitizers composed of vinyl sulfide, vinyl urethane, urethane acrylate and vinyl urea.

The resin composition of the present invention may also contain various kinds of additives.

Examples of suitable additives are resins or polymers such as epoxy resins, polyamides, polyamideimides, polyurethanes, polybutadiene, polychloroprene, polyethers, polyesters, styrene / butadiene styrene block copolymers, petroleum resins, xyl Lene resins, ketone resins, cellulose resins, fluorine-containing oligomers and silicon-containing oligomers; Polymerization inhibitors such as phenothiazine and 2,6-di-t-butyl-4-methyl phenol; Polymerization initiation aids, leveling agents, wetting improvers, surfactants, plasticizers, ultraviolet absorbers, silane coupling agents, resin particles, pigments and dyes.

The resin composition of the present invention is a filler component (E) in a homogeneous resin solution after mixing the above-mentioned components (A) to (D), (F) and (G), optional components and additives into a homogeneous resin solution It can be prepared by dispersing. For example, other methods of mixing are also possible in which the order of addition of the components is changed. These and other methods are generally known to those skilled in the art.

The present invention also relates to a method of forming a three-dimensional object comprising the following steps:

(a) coating a layer of viscosity reducing composition on the surface,

(b) making the layer a viscosity reducing composition layer having a higher viscosity than the viscosity reducing layer,

(c) exposing the viscosity reducing layer along the radiation image by a radiation method to form light along the layer; and

(d) repeating steps (a) to (c) until a three-dimensional object is formed.

Test Methods

The following test method is used to determine the yield stress and viscosity versus shear rate of the paste sample of the present invention. Measurements use the SR5 Stress Flowmeter manufactured by Rheometric Scientific Inc. The following settings:

Test type: normal rotation system.

Geometry: Parallel plate, 25mm diameter and 1.0mm thickness.

Time: 25 ° C., controlled by parallel Peltier plates.

Onset stress: 20 Pa.

Final stress: 10 ⁴ Pa.

Maximum time per data point: 15 seconds.

Delay time: 10 seconds delay before start test.

Techniques for sample loading are standards known to those skilled in the art when using flowmeters. Start running when the sample is loaded and the excess material is removed from the plate edges. The run provides three kinds of graphs: (1) shear rate versus shear stress, log-log scale; (2) shear stress versus shear rate, two scale linear; And (3) viscosity versus low speed, log-log scale. The point obtained is defined as a point in the shear-velocity versus shear stress curve (1), where the velocity is equal to 10 ⁻² sec ⁻¹ . The yield stress value is defined as the shear stress at which the first shear rate exceeds 1 × 10 ⁻² seconds ⁻¹ . The plot of viscosity versus shear rate (3) does not result from isolation experiments but from the redrawing of data already present in the original data set. There is already some sort of point related to shear stress and shear rate. Viscosity is defined as the shear stress divided by the shear rate, so the viscosity is calculated programmatically and available for drawing.

Test Method to Determine Recovery Time (Example 2)

Recovery measurements are performed with a Rheometric Scientific ARES-LS power machine analyzer with concentrated cylinder geometry. Cylinder diameters were 25 to 27 mm each. Prior to loading into the concentration cylinder system, the samples were manually stirred for at least 1 minute. After loading the sample, a so-called normal shear experiment was performed for 15 seconds at a shear rate of 100 seconds ^-1 . Immediately after the normal shear experiment, the instrument was exchanged by power and the so-called time settled to a fixed angular frequency of 1 rad sec ^-1 and started 0.3% strain amplification. In summarizing this time, power viscosity and depreciation were investigated as a function of time to examine the recovery of the sample structure. The test temperature was 23 ° C. The viscosity of the sample was considered recovered when the viscosity of the sample was at least 95% of the initial value of the viscosity.

Determination of Filler Settling Rate

Filler fixation rate (or settling rate) of the formulation was determined as follows: Freshly prepared paste of test tubes (area height 150 mm, outer diameter 20 mm and inner diameter 17 mm) below 120 mm (one tube for all compositions). -Filled with similar composition. Test tubes were stored at room temperature in a place free of drafts protected from light at room temperature and the level of the clear solution on top of the resin in each test tube was measured every 24 hours. The fixation rate was determined by measuring fixation for 15 days and measuring the average settling per day by regression analysis.

Example 1

Effect of Flow Aid on Yield Stress

Paste-like compositions were prepared by mixing the following ingredients.

Base composition is 23.4% by weight UVR-1500, 8.74% by weight Heloxy 67, 3.91% by weight SR-351, 2.42% by weight DPHA, 0.02% by weight 4-methoxyphenol, 60.54% by weight NP-100, 0.41% by weight aerosil 200 % And vinyl trimethoxysilane were prepared by mixing 0.61% by weight. The base composition does not contain Ir-184 and CPI 6976 because these compounds do not require rheology testing. The presence or absence of the photoinitiator does not substantially change the rheological behavior of the resin. The absence of photoinitiators has the advantage of increased light stability of the resin during manufacture and running of rheological samples. The addition of 0.66 wt% Ir-184 and 3.79 wt% CPI 6976, for example, provides an ultraviolet curable resin, which can be cured, for example, from ultraviolet light from a solid state laser. It is within the discretion of the person skilled in the art to determine the amount of photoinitiator to obtain the optimal photoreaction (similar to the curing depth (Dp)) for the experiment.

Different amounts of thixotropic agent and flow aid were added to the base composition. Flow characteristics (yield stress, viscosity and filler fixation rate at shear rates of 1, 10 and 100 sec ⁻¹ ) were measured according to the procedure described above. The results are summarized in Table 2 below.

Most of the samples do not exhibit any fixability except samples C1, C6 and C7. Development of the settlement occurred as shown in Table 3 below:

Example 2

Effect of Thixotropes and Flow Aids on Recovery Time

The recovery time of the resins according to the invention was studied. Eight compositions from Example 1 were subjected to shear experiments, where the recovery of viscosity was studied after applying normal shear for a short time. The recovery time of each sample was determined after the first normal shear (for 1 second) and repeatedly after 60 seconds of the second shear. The recovery index is the recovery time after the second shear divided by the recovery time after the first shear. Recovery indices of 1 to 5 represent compositions having desirable recovery properties. Preferably the recovery index is 1-2.

Claims (18)

A viscosity reducing radiation curable composition comprising at least one radiation curable component and a filler and having the following properties: (i) a yield stress value of less than 1100 Pa, (ii) 1 to 1500 Pa.sec of viscosity (at shear rate of 1 sec ^-1 ), and (iii) filler fixation rate less than 0.3 mm / day. A viscosity reducing radiation curable composition comprising at least one radiation curable component and a filler and having the following properties: (i) a yield stress value of less than 1100 Pa, (ii) viscosity (at shear rate of 10 seconds ⁻¹ ) 1 to 200 Pa sec, and (iii) filler fixation rate less than 0.3 mm / day. The method according to claim 1 or 2, A radiation cured composition having a yield stress value of less than 500 Pa. The method according to any one of claims 1 to 3, A radiation curable composition comprising at least one photoinitiator. The method according to any one of claims 1 to 4, A radiation curable composition having a thixotropy index of 3 or more. The method according to any one of claims 1 to 5, A radiation curable composition containing a thixotropic agent. The method of claim 6, Thixotropes consist of Thixcin R, Thixatrol 1, Thixartrol GST, Thixartrol ST, Aluminum stearate 132 and 22, MPA 14, Ken react LICA 38 and KR 55 Radiation curing composition selected from. The method of claim 6, A radiation curable composition wherein the thixotropic agent is selected from the group consisting of thicinsin R, thixatrol 1, thixatrol GST and thixatrot ST. The method according to any one of claims 1 to 8, A radiation curable composition comprising a flow aid. The method of claim 9, Radiation curing composition wherein the flow aid is selected from the group consisting of polyacrylates and polyalkyleneoxide modified polydimethylsiloxanes. The method of claim 9, The radiation curable composition in which the flow aid comprises Modaflow 2100. The method according to any one of claims 1 to 11, A radiation curable composition that recovers viscosity within 300 seconds after 1 second normal shear. The method according to any one of claims 1 to 12, A radiation curable composition comprising a cationic curable component and a radical curable component. The method of claim 9, A radiation curable composition comprising 30 to 90% by weight of cationic curing component. The method according to any one of claims 1 to 14, Radiation curing composition comprising 5 to 50% by weight of the radical polymerization component. 5 to 70% by weight of bifunctional epoxy compound, 0.1-15% by weight of acrylate having greater than 2 functionality, 0.1 to 10% by weight of thixotropic agents, 0.01-5% by weight of a flow modifier, and 10 to 90 weight percent of the filler and the one or more photoinitiators A viscosity reducing radiation curable composition comprising a. The method of claim 16, A radiation curable composition having the following characteristics: (i) a yield stress value of less than 1100 Pa, (ii) viscosity (at shear rate of 1 second ^-1 ) 0-1500 Pa sec, and (iii) filler fixation rate less than 0.3 mm / day. (a) coating a layer of a viscosity reducing composition according to any one of claims 1 to 16 on a surface, (b) making the layer a viscosity reducing composition layer having a higher viscosity than the viscosity reduced layer, (c) imaging exposure of the viscosity reducing layer by radiation means by means of radiation for imaging; (d) repeating steps (a) to (c) until a three-dimensional object is formed Method of forming a three-dimensional object comprising a.